The scrum is "just becoming a shitfight" under the new engagement sequence, "a free-for-all" that negates the advantage awarded to the "team that didn't make the mistake that led to the scrum", former All Blacks front-rower Craig Dowd says.

Dowd, was speaking the wake of criticism from Michael Cheika and Todd Blackadder, the New South Wales Waratahs and Crusaders coaches talking about infringements at the set-piece in their teams' games at the weekend.

Cheika said after his Waratahs had lost to the Brumbies: "The amount of time it's taking to set the scrums. It's just taking far too long," Cheika said. "You want the ball in, you want to play, but we wasted an unbelievable amount of time at scrummage. Everyone would like that, me included, especially when you're chasing games."

Blackadder, meanwhile, complained that the Crusaders were not rewarded fully for their strong scrum against Melbourne Rebels, lamenting "reset after reset" in saying the "stop-start nature of the game makes it hard to get anything going".

Blackadder said that Australian referee James Leckie could have "give[n] out some yellows" while Rebels loose-head prop Toby Smith struggled against Owen Franks, adding that the official "took a lot of our momentum away from our attack by their continuous infringements",

"By half-time I don't think we had strung any more than four phases together and even if we did we were getting penalties for them. It was one of those games where it went from a couple of phases to a set-piece."

Dowd, who played 60 Tests for New Zealand between 1993 and 2000, suggested that referees' involvement should be reduced, saying the officials have been compromised by having to call the scrum in before giving a non-verbal signal to the halfbacks to feed the ball.

"A dominant scrum should get the reward," the ESPNscrum columnist told Fairfax Media in New Zealand. "The referee getting involved with trying to guess what is happening up front is just [silly]. "Unless they can see something glaringly obvious that is happening, they should leave it alone. And I don't think referees have picked up a whistle to get involved in the dark arts of scrummaging."

Dowd also told Fairfax that the International Rugby Board should review the Law that prevents props from placing a hand on the ground to prevent a scrum from collapsing. "If props put their hand on the ground, then big deal," the ESPN columnist said. "If they get an advantage out if it, then great. And it could stop a scrum from collapsing."